Prosecutors say a woman in Utah snuck into her ex’s apartment and then shot his new girlfriend dead in front of their 3-year-old twin sons

Chelsea Watrous Cook, 32, snuck into her ex-husband’s apartment on November 25 and shot dead his new girlfriend, 26-year-old Lisa Vilate Williams, according to documents filed in court this week.

Williams was killed as she was decorating a Christmas tree with Cook’s 3-year-old twin sons.

Cook faces charges of aggravated murder, aggravated burglary, domestic violence, felony discharge of a firearm, and two counts of violence in the presence of a child.

A 32-year-old high school health teacher lured her ex-husband out of his apartment so she could sneak in and kill his new 26-year-old girlfriend, according to court documents filed this week in Utah.

Chelsea Watrous Cook could face the death penalty after being charged with aggravated murder on Wednesday, among a slew of other charges.

According to prosecutors, Cook drove over to her ex-husband Travis Cook’s apartment in Midvale just before 7 p.m. on November 25, saying she needed to drop off some cold medication for one of their three-year-old twin sons.

Security footage reportedly shows Cook lying in wait in a hallway of the building while her ex left the apartment to come out and meet her in the parking lot. She was then able to get into the apartment because he left the front door unlocked, charging documents KUTV obtained say.

At the time, Travis’ news girlfriend, Lisa Vilate Williams, was decorating their Christmas tree with the kids.

When Travis returned to the apartment, his wife was inside and refusing to leave despite repeated commands to do so, according to the filing, and she locked herself in a bathroom when he started to call 911.

As he was on the phone with 911, the documents say Travis saw his wife reach for her coat again, and fearing that she had another weapon, he lunged for her and pinned her against a wall and ordered his boys to go to their rooms and lock the door.

Cook was taken into custody when police arrived on the scene soon after.

Immediately after news of the shooting broke, Cook was fired from her job as a health and yoga teacher at Skyridge High School in Lehi, Deseret News reported.

She remains in Salt Lake County Jail without bail. It’s unclear when her trial will start.

According to Williams’ mother, Tawny, Cook had been harassing her daughter.

The court documents also show that about a month before the shooting, Williams came up in a dispute between the Cooks in which the police were called.

Travis was trying to pick up his kids from his ex on October 16 when she made “disparaging comments” about his girlfriend, according to a police report the AP obtained. When he prompted one of his sons to say he was excited to see Williams, Cook reportedly grabbed her ex by his hair, causing him to tumble down a set of stairs.